1. Technical Field
This invention relates generally to fluid injection devices, methods and systems and is particularly directed to improved automatic fertilizer injection and water line purging devices, methods and systems for lawn maintenance.
2. State of the Art
Lawn fertilizing has always been a labor intensive operation that required the caregiver to fill a sprinkler or spreader with fertilizer and manually roll it across the lawn to deliver the fertilizer. For many years now, liquid fertilizers have been available and have been widely used by attaching a siphoning container to a hose and allowing the flow of the hose to siphon the fertilizer for delivery to the lawn. However, this approach still requires considerable time, resources and manual labor in order to attach the container to the hose and to direct the hose in watering and applying the fertilizer, and to detach the hose and store the component parts between uses.
Today many, if not most, lawns are therefore watered by automatic sprinkler or emitter systems. These eliminate the manual labor of watering the lawn and ensure that the lawn is watered at a convenient time. Most commercial and residential irrigation systems are “in ground” systems, which means that everything is buried in the ground. With the pipes, sprinklers, emitters (drippers), and irrigation valves being hidden, it makes for a cleaner, more presentable landscape without garden hoses or other items having to be moved around manually. This can, however, create some drawbacks in the maintenance of a completely buried system.
Most irrigation systems are divided into zones. A zone is a single irrigation valve having one or a group of drippers or sprinklers that are connected by pipes or tubes. Irrigation systems are divided into zones because there is usually not enough pressure and available flow to run sprinklers for an entire yard or sports field at once. Each zone typically has a solenoid valve that is controlled via wire by an irrigation controller. The irrigation controller is either a mechanical or electrical device such as a timer that typically signals a zone to turn on at a specific time and keeps it on for a specified amount of time. The irrigation controller therefore typically activates and deactivates the irrigation system on demand. Most irrigation controllers have means for setting the frequency of irrigation, the start time, and the duration of watering, for example. However, some controllers have additional features such as multiple programs to allow different watering frequencies for different types of plants, rain delay settings, input terminals for sensors such as rain and freeze sensors, soil moisture sensors, weather data, remote operation, and the like and keep it on for a specified amount of time.
When a zone comes on, the water flows through the lateral lines and ultimately ends up at the irrigation emitter (drip) or sprinkler heads. Many sprinklers have pipe thread inlets on the bottom of them which allows a fitting and the pipe to be attached to them. The sprinklers are usually installed with the top of the head flush with the ground surface. When the water is pressurized, the head will pop up out of the ground and water the desired area until the valve closes and shuts off that zone. Once there is no more water pressure in the lateral line, the sprinkler head will usually retract back into the ground. Emitters are generally laid on the soil surface or buried a few inches to reduce evaporation losses.
Fertigation is the application of fertilizers, soil amendments, or other water-soluble products through an irrigation system. Fertigation can provide plants with essential nutrients through the plant's leaves and roots. Furthermore, because most of the fertilizer gets absorbed directly into the plant, fertilizer run-off is virtually eliminated. Fertigation can also improve a plant's efficiency in holding water through an increase in root mass, thereby reducing total water needed. Fertigation means and methods can also potentially dispense more than just fertilizers, including repellants/controls as well as soil supplements and bio-stimulants in order to address other landscape concerns. Chemigation, a related and sometimes interchangeable term, is the application of chemicals through an irrigation system. Chemigation is considered to be a more restrictive and controlled process due to the potential nature of the products being delivered—typically pesticides, herbicides, fungicides—to cause harm to humans, animals, and the environment.
Fertigation can be achieved in a number of ways. Solid fertilizer pellets can be added to a mesh-like container positioned close to a single emitter, for example. Another approach is to manually place a mixing receptacle such as a bottle or jar in line, the receptacle typically having a cartridge containing concentrated liquid fertilizer that can be diluted in the tank and then injected into the irrigation system. Yet another approach is to use a container that can release small, precision doses of water soluble or liquid fertilizers into the water stream automatically. Problems with such approaches arise, for example, with the need to manually remove an in line fertilizer container from an automated irrigation system if a user wants to water without fertiziation, or the need to manually add fertilizer to the emitter-container type system.
Another major problem facing automatic watering systems, especially in cold climates, has been the need to purge the line to prevent freezing. In the past, this has been a very labor intensive operation and has frequently meant that, once purged, the automatic watering system would not be used again for several months until the freeze danger had passed.
Thus there remains a need for improved apparatuses, methods and systems that can inject liquids into and purge water lines, on demand, without interfering with usage of the system. And, in particular, there is a need for automated systems capable of injecting fertilizers into and purging sprinkler system within the lawn maintenance industry.